A day after a federal judge struck down the government's plan to overhaul the health-care system, Wisconsin Attorney General J.B. Van Hollen issued a stern statement: "This means that, for Wisconsin, the federal health care law is dead," and that his state "was relieved of any obligations or duties" to carry out the statute.

Colorado Gov. John Hickenlooper (D), meanwhile, pointed to the 700 people in his state with serious medical problems who already found insurance under the law. "Who goes to these people," the governor said in an interview, "and tells them, 'Sorry, a judge in Florida has decided we now need to put you out in the cold?' "

Wisconsin and Colorado are among the 26 states joined in the legal challenge that prompted Monday's opinion by U.S. District Judge Roger Vinson in Pensacola, Fla., that the law is invalid because it goes too far in requiring most Americans to buy health insurance. The reactions from Van Hollen and Hickenlooper reflect striking disagreement over the ruling's practical effects, even for the states in which the decision has the greatest direct impact.

Officials in Idaho and Florida, the state that initiated the lawsuit last March, said the ruling gives them the freedom to stop the work they have begun to put the law into effect. "We are not going to spend a lot of time and money with regard to trying to get ready to implement it," Florida Gov. Rick Scott (R) told reporters in Tallahassee.

Meanwhile, the governors of Georgia, Iowa and Mississippi said through spokesmen that they did not think the court decision gave them license to stop work on the law, in part because the ruling is destined to be appealed to higher courts. "The state cannot halt midstream, because that would be irresponsible," said Brian C. Robinson, communications director for Georgia Gov. Nathan Deal (R), inaugurated last month after years in Congress. "It would put us too far behind if our litigation is not successful in the end." Officials in some of the other 26 participating states said they simply have not yet determined what the ruling means in practice.

The interpretations by these states are significant because, under the ruling, only the direct parties to the case potentially are exempt from the law's requirements, according to the plaintiff's attorney, David Rivkin. At issue, he said, are sweeping changes to the nation's health-care system that the law delegates to states. They include an expansion of Medicaid, the public insurance program for low-income Americans, so that it becomes available to people with higher incomes. They also include the design of insurance "exchanges," new-fangled marketplaces through which individuals and small businesses will be able to buy coverage. Both changes are to take effect in 2014 and require a lot of preparations.

However, Rivkin said, the ruling does not touch any provisions of the law that relate to insurance companies and employers, because they are not part of the lawsuit. This means, for instance, that the opinion does not jeopardize some aspects of the law that already have gone into effect, including the ability of young adults to remain longer on their parents' insurance policies.

As states struggled to parse the meaning of the ruling, the decision elated congressional Republicans, who are waging a parallel effort to dismantle the law.

The House, where Republicans became the majority last month, already has passed a bill to repeal the law. On Tuesday, Senate Republican leaders announced that they intend to try Wednesday to force the same measure to a vote in the Senate, where Republicans remain in the minority. Senate Minority Leader Mitch McConnell (R-Ky.) proposed the repeal legislation as an amendment to an unrelated bill - involving funding for the Federal Aviation Administration - that is the first the Senate will consider since the start of the new Congress. Senate Democrats said Tuesday, however, that they intend to use a parliamentary maneuver to try to obstruct the vote.

Democrats are more receptive to another amendment, sponsored by Sen. Debbie Stabenow (D-Mich.), which would eliminate a provision that increases the burden on small businesses in filing tax forms. That provision is the one aspect of the law that President Obama and many congressional Democrats have said they are willing to abolish.

Also Wednesday, Senate Majority Whip Richard J. Durbin (D-Ill.) is scheduled to lead a hearing in the Senate Judiciary Committee to examine the constitutionality of the law. Democrats maintain that the law is constitutional, while Republicans, including state officials in 25 of the 26 states participating in the case that led to Monday's ruling, maintain that the insurance requirement and other provisions exceed Congress's constitutional limits.

In his decision, Vinson did not issue an injunction formally blocking the law, reasoning that one was unnecessary because his opinion was "the functional equivalent." Justice Department spokeswoman Tracy Schmaler said the agency is considering whether to request a stay, to clarify that the work of putting the law into practice can go on during court appeals.

Legal scholars interviewed Tuesday, including some who have held senior positions in Republican administrations, said the judge's legal reasoning that his ruling amounted to an injunction was unusual."I think the judge has misread some of the precedents he cites," said William Buzbee, a law professor at Emory University.